Chiral Van Der Waals Superlattices for Enhanced Spin-Selective Transport and Spin-Dependent Electrocatalytic Performance.

Abstract

The emergence of the chiral-induced spin-selectivity (CISS) effect offers a new avenue for chiral organic molecules to autonomously manipulate spin configurations, thereby opening up possibilities in spintronics and spin-dependent electrochemical applications. Despite extensive exploration of various chiral systems as spin filters, one often encounters challenges in achieving simultaneously high conductivity and high spin polarization (SP). In this study, a promising chiral van der Waals superlattice, specifically the chiral TiS₂ crystal, is synthesized via electrochemical intercalation of chiral molecules into a metallic TiS₂ single crystal. Multiple tunneling processes within the highly ordered chiral layered structure of chiral TiS₂ superlattices result in an exceptionally high SP exceeding 90%. This remarkable observation of significantly high SP within the linear transport regime is unprecedented. Furthermore, the chiral TiS₂ electrode exhibits enhanced catalytic activity for oxygen evolution reaction (OER) due to its remarkable spin-selectivity for triplet oxygen evolution. The OER performance of chiral TiS₂ superlattice crystals presented here exhibits superior characteristics to previously reported chiral MoS₂ catalysts, with an approximately tenfold increase in current density. The combination of metallic conductivity and high SP sets the stage for the development of a new generation of CISS materials, enabling a wide range of electron spin-based applications.